The project entails an investigation of the basis for the observed biological properties (mutagenicity, carcinogenicity) of polycyclic aromatic hydrocarbons (PAH) and nitrogen-substituted PAH, Dihydro, dihydrodiol, diol epoxide and other derivatives on benzo rings of PAH such as benzo(a)pyrene, dibenzo(a,i)- and (a,h)pyrene, and benz(c)acridine are to be synthesized, and their biological properties are to be examined through collaborations with other laboratories.